When, for example, a user acquires content stored in a server in a communication system on an IP network, the user accesses a search server and specifies a keyword related to the content for the search server by using a personal computer (simply referred to below as the PC). As a result, the PC acquires, from the search server, the uniform resource locator (URL) of a content name list related to the keyword.
Furthermore, the PC accesses a domain name system (DNS) server, after which the user specifies a content name from the content name list, and the PC acquires the IP address of the server that stores content corresponding to the specified content name.
Then, the PC establishes coupling with the server according to the acquired IP address and specifies a content name in http to request the server for the content. In response to the content request, the server stores the content in a content response and returns it to the PC. As a result, the PC can acquire desired content from a server in the communication system through a keyword-based content search. Related art documents include Japanese National Publication of International Patent Application No. 2008-504609, Japanese Laid-open Patent Publication No. 2007-249514, and Japanese Laid-open Patent Publication No. 2001-273298.